Search results for "frequency [modulation]"
showing 10 items of 569 documents
Contemporary Outcomes for the Curative Treatment of Colorectal Cancer Pulmonary Metastases.
2023
Purpose: Treatment of pulmonary metastases (PM) from colorectal cancer (CRC) is the standard of care by several guidelines from Europe and the USA, but the validity of this strategy has been recently questioned, and the available evidence supporting this strategy is weak. We report the outcomes of a curative intent strategy in a very recent and homogenous series of patients. Methods: We did a retrospective review of all curative intent surgical or ablative treatment of PM from CRC performed consecutively in 3 French institutions from January 2015 to December 2019. Demographics, clinicopathological, and molecular characteristics were evaluated. Cox regression models were used to identify pro…
Radiofrequency ablation for thyroid nodules: which indications? The first Italian opinion statement
2015
Nodular thyroid disease is a very common finding in clinical practice, discovered by ultrasound (US) in about 50 % of the general population, with higher prevalence in women and in the elderly [1–4]. Whereas therapeutic flowchart is quite established and shared for malignant lesions, multiple options are now available for patients presenting with benign thyroid nodules, ranging from simple clinical and US follow-up to thyroid surgery. The majority of thyroid nodules, benign by fine-needle aspiration, are asymptomatic, stable, or slow-growing over time and require no treatment. Nevertheless, large thyroid nodules may become responsible for pressure symptoms, resulting in neck discomfort, cos…
Intracavity Frequency Doubling and Difference Frequency Mixing for Pulsed ns Ti:Sapphire Laser Systems at On-Line Radioactive Ion Beam Facilities
2015
Intra-cavity second harmonic generation of a Titanium:sapphire (Ti:sa) laser system has been used to improve the conversion efficiency to the second harmonic. Over the course of several experiments performance data spanning the whole wavelength range of a Ti:sa has been collected, which may be used as a guideline for future experiments. An average output power of up to 3.7 W was achieved, resulting in a conversion efficiency of >75 % to the second harmonic. A wavelength coverage from 340-525 nm has been demonstrated. To extend the wavelength range of the solid state laser system, difference frequency mixing has been applied to the intra-cavity doubled light and the fundamental output of a s…
Regularization Method in Infrared Image Processing
2003
Abstract Infrared images often present distortions induced by the measurement system. Thus, image processing is a vital part of infrared measurements. A distortion model based on a convolution product is presented. Image restoration is an ill-posed problem and its solution can be obtained using regularization methods. In this paper, image restoration is performed using a variation of Tikhonov regularization that makes use of the particular form of the convolution kernel matrix, which is built as a block-circulant matrix that admits a diagonal form in the two-dimensional Fourier space. The restoration procedure is used to restore a knife-edge infrared source image.
Effect of fatigue on the intra-cycle acceleration in front crawl swimming: a time-frequency analysis.
2007
The present study analyzes the changes in acceleration produced by swimmers before and after fatiguing effort. The subjects (n=15) performed a 25-m crawl series at maximum speed without fatigue, and a second series with fatigue. The data were registered with a synchronized system that consisted of a position transducer (1 kHz) and a video photogrametry (50 Hz). The acceleration (m s−2) was obtained by the derivative analysis of the variation of the position with time. The amplitude in the time domain was calculated with the root mean square (RMS); while the peak power (PP), the peak power frequency (PPF) and the spectrum area (SA) were calculated in the frequency domain with Fourier analysi…
Concurrent fast and slow synchronized efferent phrenic activities in time and frequency domain.
1990
Abstract In urethane-anesthetized or decerebrated vagotomized rabbits efferent multifiber activity of the phrenic nerve was investigated for synchronized activities both in time and frequency domains. When respiratory drive was steadily increased by either an elevation of end-tidal CO2 concentration or i.v. administration of 4-aminopyridine, medium-frequency oscillations (MFO) first increased, then decreased and finally became absent. The power of high-frequency oscillations (HFO) steadily rose with increasing respiratory drive. In contrast to HFO which revealed a unimodal spectral peak of mostly small bandwidth, the MFO spectrum in most cases consisted of a broad complex. This complex in s…
Boundedness and compactness of operators related to time-frequency analysis
2018
En esta tesis, estudiamos diferentes aspectos de los operadores relacionados con el análisis tiempo-frecuencia. Cada operador lineal y continuo de la clase de Schwartz en su dual, el espacio de distribuciones temperadas, se puede escribir como un operador integral con núcleo K, o también como un operador integral de Fourier (de hecho, pseudodiferencial). Las diferentes condiciones en el núcleo o el símbolo y la fase (en el caso de los operadores integrales de Fourier) permiten extender el operador a varios espacios de funciones y distribuciones. A continuación detallamos los contenidos de la memoria. En el primer capítulo presentamos la notación, las definiciones de algunos espacios, de suc…
Audiologic profile of OSAS and simple snoring patients: the effect of chronic nocturnal intermittent hypoxia on auditory function
2016
The objective of this work was to study the effect of nocturnal intermittent hypoxia on auditory function of simple snoring patients and subjects affected by OSAS; we compared the audiologic profile with the severity of OSAS to detect early signs of cochlear damage. One hundred-sixty patients underwent overnight polysomnography, micro-otoscopy, multi-frequency audiometry, acufenometry, TEOAE recording and d-ROMs test. All subjects were divided in four groups, based on presence/absence of AHI (simple snoring without OSAS, mild OSAS, moderate OSAS, severe OSAS). Sixty (37.5 %) patients were not affected by OSAS, 58 (36.25 %) presented a mild OSAS, 18 (11.25 %) a moderate OSAS and 24 (15 %) a …
Performance evaluation of the MPE-iFEC Sliding RS Encoding for DVB-H streaming services
2008
This article studies the performance of the Sliding RS Encoding (SRSE) in the transmission of streaming services in DVB-H (Digital Video Broadcasting - Transmission System for Handheld Terminals) networks. The SRSE forms part of a set of specifications called MPE-iFEC which has been recently defined in the DVB-SH (Digital Video Broadcasting - Satellite Services to Handheld Devices) standard and is fully compatible with the link layer of DVB-H. MPE-iFEC is capable of encoding information related to different datagram bursts in a jointly manner in order to counteract the long signal blockages expected in satellite reception. This is what is usually referred to as Multi-Burst Encoding (MBE) an…
Increasing the performance of HSDPA with high-speed single frequency network
2012
High Speed Single Frequency Network (HS-SFN) is a multi-cell transmission scheme for High-Speed Downlink Packet Access (HSDPA) that can assist user equipment (UEs) in the softer handover area by combining signals from two neighbouring cells and at the same time by reducing the inter-cell interference. This article analyzes performance of HS-SFN for macro cell scenario under different channels with different type of schedulers by means of extensive system level simulations. The results indicate that HS-SFN can increase throughput for UEs in softer handover area from 40% to 80% without decreasing the overall performance.